A non-U.S. citizen who has been given permission to make a permanent home (and work) in the United States. Permanent residents are given "green cards" (also called Alien Registration Cards or ARCs or I-551s) to prove their status. U.S. permanent residents may travel outside the country as much as they like, but their place of residence must remain in the United States and they must keep that residence on a permanent basis. Otherwise, they'll be said to have abandoned their U.S. residence, and could lose their right to the green card. Permanent residents who leave the United States and stays away for more than six months risks having the U.S. immigration officials believe that they abandoned residence.